There have been provided in the past a number of floating dock structures and the principal floatation medium has been a polystyrene foam block. The foam, however, has a tendency to break off in chunks. This is not environmentally acceptable. In addition, the pontoons, as they are sometimes known, do not readily withstand the natural abuse of the environment and are easily fouled with marine growth. Typical floating docks are seen, for example, in Dunlop, U.S. Pat. No. 4,223,629, that discloses a rectangular frame supporting a wood plank decking maintained afloat by blocks of floatation material. These exists, however, a need for a floatable load-supporting dock structure which can be put together in uniform sections and disassembled rapidly for winter storage and the like and which are relatively light so that they may be transported with minimal cost and inconvenience.